• The Korean Journal of Pesticide Science
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• v.10 no.1
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• pp.56-65
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• 2006

An antagonistic bacterial isolate, that inhibits the growth of plant pathogens, was selected and identified from 5,000 isolates screened from the rhizosphere of various crop plants. An isolate Bacillus sp. N32, tested against Colletotrichum gloeosporioides causing anthracnose disease in hot pepper, produced both a heat resistant antifungal protein and a heat sensitive antifungal protein. The heat resistant protein was partially purified by Ammonium sulfate fractionation and gel filtration chromatography. The bioautography showed that the proteins possessed high antifungal activity. The biosynthetic gene cluster responsible for the heat resistant antifungal protein was cloned from cosmid library using DNA probe obtained from PCR product with the primers targeting the conserved nucleotide sequence of the synthetic genes reported earlier, Most of the clones obtained showed higher homology to fengycin antibiotic synthetic gene family reported earlier. On the other hand, the heat sensitive protein was isolated from SDS-PAGE and electroblotting to determine the N-terminal amino acid sequences. The heat sensitive antifungal protein gene was cloned from the ${\lambda}-ZAP$ libraries using a DNA probe based on the N-terminal amino acid sequences of the heat sensitive protein. We are contemplating to clone and sequence the whole gene cluster encoding the heat sensitive protein for further analysis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.1
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• pp.1-11
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• 2014

This study was carried out to investigate nutritional and physiologically active characterizations of sikhae and the seasoned products from the sea squirt Halocynthia roretzi. The total taste values of sikhae fermented for 4 and 5 days were 10.9 and 15.4, respectively, which was lower than for commercially seasoned sea squirts. The sikhaes contained mostly glutamic and aspartic acids. The total amino acid contents of sikhaes fermented for 4 and 5 days were 5.5 and 6.0 g/100 g, respectively, which were lower than those of commercial seasoned-sea squirts or similar. An amount of 100 g of sikhae and its seasoned products contained P, K, Mg and Fe, and these minerals, which are deemed good for our health, were at 10% above the recommended daily requirements. The functional properties of sikhae fermented for 4 and 5 days were as follows: for ACE inhibiting activity, 69 and 69.5%, respectively; for antioxidative activity, 28.9 and 29.3%, respectively; for xanthine oxidase inhibitory activity, 52.8 and 53.1%, respectively; and for ${\alpha}$-glucosidase inhibitory activity, 2.4 and 1.4%, respectively. Antimicrobial activity of the 5 day fermented sikhae against Vibrio parahaemolyticus and Staphyloccus aureus was detected in 8 mm and in 7 mm against Escherichia coli.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.339-346
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• 2007

The MJP1 bacterial strain, which possesses antifungal activity, was isolated from meju and identified as Bacillus subtilis based on its morphological and biochemical properties, as well as its 16S rRNA sequence. Antimicrobial activity was found against various species of Gram-positive bacteria, yeasts, and molds, including food-spoilage microorganisms. The antifungal activity was found to be stable after heat and proteolytic enzyme treatment, and in the pH range of $6.0{\sim}10.0$. The antibacterial activity was stable in the pH range of $6.0{\sim}10.0$, but about 50% of the activity was lost after 24 hr at $30^{\circ}C$. The antibacterial compound was also inactivated by proteolytic enzyme treatment, indicating its proteinaceous nature. The apparent molecular masses of the partially purified antifungal and antibacterial compounds, as indicated by using the direct detection method in Tricine-SDS-PAGE, were approximately 2.4 kDa and 4.5 kDa, respectively. These studies suggest that B. subtilis MJP1 produces two bacteriocin-like substances with antifungal and antibacterial activities.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.121-127
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• 2008

A strain IDCC 9203 isolated from infant feces was identified as Lactobacillus johnsonii on the basis of 16S rDNA sequence analysis. L. johnsonii IDCC 9203 was highly resistant to acid (MRS broth at pH 2.3) and bile (MRS broth with 0.3% oxgall). The antibacterial activities of L. johnsonii IDCC 9203 was examined against Salmonella typhimurium KCTC 2054. The growth of S. typhimurium KCTC 2054 was inhibited by the cell-free culture supernatant (at pH 4.0) of L. johnsonii IDCC 9203 as well as by the respective control (MRS broth at pH 4.0). Antimicrobial effect against S. typhimurium KCTC 2054 of L. johnsonii IDCC 9203 was probably due to the lactic acid. By an in vitro cell adhesion model, L. johnsonii IDCC 9203 preincubated or coincubated with Caco-2 cells reduced the adhesion of S. typhimurium KCTC 2054 to Caco-2 cells by 74% or 47.1%, respectively. Also in an in vivo model, L. johnsonii IDCC 9203 was colonized in mice intestines which were disrupted by ampicillin treatment. Its proliferation in the mice intestines reduced abnormal salmonella growth from $10^9CFU/g$ feces to $10^5CFU/g$ feces as an indigenous level. The results obtained in this study suggest that L. johnsonii IDCC 9203 may be a potential probiotic strain.

• Microbiology and Biotechnology Letters
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• v.41 no.4
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• pp.416-424
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• 2013

In the course of a study for the development of functional foods utilizing Woosul (Achyranthis radix), the components and various biological activities of Korean Woosul (AJN: Achyranthes japonica Nakai) and Chinese Woosul (ABB: Achyranthes bidentata Blume) were compared. Woosul in Korea, including AJN and ABB, are regulated and part of the Korean Pharmacopoeia. From AJN and ABB, ethanol extracts and their subsequent organic solvent fractions were prepared and their in-vitro antimicrobial, antioxidant and anti-diabetes activities were evaluated. Although AJN and ABB have no clear distinction in terms of usage in Korea, our results suggest that AJN has higher quantities of lipid-soluble components and lower amounts of water-soluble sugars than does ABB. ABB also appears to possess greater amounts of flavonoid and polyphenol substances than AJN. Analyses of biological activities showed that the fractions of AJN were more active as antibacterial agents, and possessed more pronounced ${\alpha}$-glucosidase inhibitory activities than those of the ABB fractions. However, the antioxidant activities of the ABB fractions, as determined by DPPH anion-, ABTS cation-, nitrite-scavenging activity and reducing power, were higher than those of the AJN fractions. Our results suggest that the components and bioactivity of the extracts and subsequent fractions of AJN and ABB are different. Therefore, usage of either AJN or ABB should be carefully considered, as regards their individual properties, when the active fractions of Woosul are employed in the development of functional foods or novel plant-derived medicines.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.542-549
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• 2018

In this study BGn-incorporated non-fluoride release of pit and fissure sealant $Concise^{TM}$ was developed to improve the mechanical properties and promote antibacterial effect of fit and fissure sealant with the original material. The mechanical properties and antibacterial activity of BGn incorporating vary-ing amounts bioactive glass nano particles(BGn) (0,0.5,1.0 and 2.0 wt% in sealant) were characterized composition of the resulting were investigated. The solubility to aid absorption was calculated by weighing specimens with a diameter of 10 mm and a thickness of 2 mm according to ISO 4049 (2009). The antimicrobial effect was evaluated using three strains of S. mutans, S. aureus and E. coli. The absorbance of the test results was as high as the addition of BGn increased, and the lower the solubility as the solubility was added(p<0.05). Adhesion experiment results S. mutans in contrast to the control group $Concise^{TM}$, BGn-added experimental group showed a somewhat lower adherent surface but no statistically significant difference was observed (p<0.05). However S. aureus and E. coli statistical analysis indicated a significant difference for antibacterial agents between control and BGn containing(p<0.05). It seems that this BGn proved that even a antibacterial effect was demonstrated. Therefore, it was suggest that the additional effects of BGn and research on a wide range of substances.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.663-666
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• 2015

In this research, botanical extracts containing green tea, Saururus chinensis and Prunus padus were tested to see possibility as shampoo. Leaves of Green tea and Saururus chinensis were extracted with hot water. Prunus padus bark extract was applied reverse osmosis and ultrasonic extraction. When interfacial tension was measured among shampoo including botanical extracts, Sodium dodecylsulfate(SDS) and Quillaja Bark Saponin(QBS), that of shampoo was lower than that of SDS and QBS at lower concentration, however, it showed similar interfacial tension at 100% concentration. Shampoo showed moderate antimicrobial activity in Staphylococcus aureus and Candida albicans. Botanical extract did not indicate cell toxicity up to $350{\mu}g/ml$ concentration in MTT assay. Shampoo containing botanical extract was stable for 3 months, however, it showed considerable variation in pH and viscosity. In conclusion, shampoo containing botanical extract shows strong possibility for natural shampoo if the formulation is modified.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.730-739
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• 2015

108 microorganism types (79 types of fungi and 29 types of bacteria) were isolated from 25 automobiles generating bad odor when the air conditioner was turned on, and 43 types of fungi and 23 types of bacteria were identified. The analysis of condensate generated by the air conditioners in the automobiles indicated pH 6.4~7.1, 12.5~34.2 mg/L carbon source, 0.9~18.6 mg/L nitrogen source, 0.5~27.8 mg/L ion contents, and 0.1~7.7 mg/L mineral contents. The biofilms were formed by the mesophiles under the summer temperature/humidity condition ($26^{\circ}C$, 70% R.H.), and they were regenerated when the environmental factors (nutritional contents and temperature/humidity) were appropriate even after they were artificially removed. Although the antimicrobials removed 99.9% of planktonic cells within 15 minutes, they were not effective in removing biofilm. Up to 1,950 ppmv of ethanol was observed in the automobile treated with the antimicrobials. Although the figure is lower than the acute toxicity level when inhaled by humans, the health safety of the chemical substances used in the antimicrobials needs to be reviewed.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.437-443
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• 2016

In this study Streptomyces strains were isolated from soils and their antifungal activities and involved mechanisms were investigated. Among over 400 isolates of actinomycetes, Streptomyces costaricanus HR391 was selected as a potential antagonist to control several plant-pathogenic fungi. S. costaricanus HR391 inhibited mycelial growth of Fusarium oxysporum f. sp. raphani, F. oxysporum f. sp. niveum, F. oxysporum f. sp. lycopersici, and Rhizoctonia solani by 26.5, 26.2, 21.2, and 23.8%, respectively compared to those of uninoculated control after 7-day incubation on PDB medium. S. costaricanus HR391 produced $89{\mu}M$ of siderphore, and showed fungal cell wall-degrading activity including $0.46{\mu}mol/min/mg$ of chitinase and $0.83{\mu}mol/min/mg$ of ${\beta}$-1,3 glucanase. S. costaricanus HR391 secreted 87.49 mg/L of rhamnolipid, and produced 9.49 mg/L and 4.3 mM of lipopeptide, iturin A and surfactin, respectively, all they are membrane-disrupting biosurfactants. It also produced antimicrobial peptide and antibiotics phenazine. In addition to antifungal substances, S. costaricanus HR391 secreted plant growth-promoting phytohormones, zeatin, gibberellins and IAA. These results suggest that S. costaricanus HR391 may be utilized as an environment-friendly biocontrol agent against some important pathogenic fungi.

• Food Science and Preservation
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• v.5 no.3
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• pp.292-298
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• 1998

The isolates from putrefying soybean curd were identified as Acinetobacter calcoaceticus, Bacillus cereus, Bacillus sp., Cardiobacterium sp., Escherichia coli, Klebsiella pneumoniae, Pantoea sp., Salmonella typhimurium, Staphylococcus aureus, Xenorhabdus luminescens, Yersinia sp.. The existence percentages of the bacteria from putrefying soybean curd at room temperature storage were Bacillus cereus J55 23.57%, Xenorhabdus luminescens J48 22.73%, Acinetobacter calcoaceticus J61 22.26%, Klebsiella pneumoniae J62 21.25%, Salmonella typhimurium J51 2.87%, Pantoea sp. J57 2.65%, Bacillus sp. J58 1.43%, Cardiobacterium sp. J54 1.26%, Escherichia coli J53 1.20%, Staphvlococcus aureus J6O 0.93%, Yersinia sp. J50 0.05%, respectively. Four out of eleven bacteria as B. cereu J55, X. luminescens J48, Ac. calcoaceticus J61, Kl. pneumoniae J62 putrefied soybean curd and those bacteria produce amylase or proteinase as a extracellular enzyme. But S. typhimurium J51, Pantoea sp. J57, Bacillus sp. J58, Cardiobacterium sp. J54, E. coli 153, St. aureus J60, Yersinia sp. J50 were not putrefied soybean curd. The isolates detected to resistant on various antimicrobial agents. The majority were resistant to aminoside antiboitics as amicacin, gentamicin, tobramycin and were susceptible to ${\beta}$-lactamine antibiotics as penicillin G, oxacillin, cephalothin cefazolin, cefamandole.